1. Field of the Invention
The present invention relates generally to a brushless direct current motor and, more particularly, to a self-starting, brushless direct current motor comprising a rotor, a stator, and a plurality of electromagnets activated by infrared phototransistors.
2. Description of the Related Art
U.S. Pat. No. 3,579,277 relates to a brushless direct current motor. Pairs of axially spaced permanent magnets are radially arranged about and fixed to a rotor shaft, and driving coils are disposed in the space between the pairs of permanent magnets. A shield ring having cutaway portions is disposed in the path of detecting coils so that when the cutaway portions are aligned with positional detecting coils, the driving coils associated with the particular detecting coils are activated to produce a driving force.
U.S. Pat. No. 4,220,879 relates to a brushless direct current motor comprising a rotor, stator, and detecting elements. The rotor includes a rotor magnet, with a number of poles, mounted on a rotor yoke which in turn is mounted on a rotor shaft. The stator includes a stator yoke and a number of stator coils disposed on the stator yoke to face the rotor magnet in a non-overlapping predetermined angular relation to each other. Wiring means are disposed on the stator yoke and are connected to the stator coils. The detecting elements are mounted on the wiring means to sense the rotational position of the rotor magnet and provide a signal by which current fed to the stator coils can be controlled.
U.S. Pat. No. 4,857,783 relates to a brushless direct current motor which comprises a rotor, a magnetic leaf switch, and a ferrous core coil winding. The rotor incorporates a flat, annular two pole permanent magnet and a rotational output shaft passing through the magnet. The magnetic leaf switch floats in the magnetic field of the permanent magnet. The ferrous core coil winding serves as a stator which is energized by direct current. Current flow to the stator is controlled in an alternating on-off manner by the magnetic leaf switch. When the stator is energized, the core assumes a polarity that repels one of the poles of the permanent magnet carried by the rotor. This repulsion causes rotation of the permanent magnet about the longitudinal axis of the rotational output shaft.
U.S. Pat. No. 4,973,869 relates to a disc type brushless, cordless direct current motor. The motor comprises a rotor, stator, armature coil, and a position detector sensor. The position detector sensor is installed below an effective coil part of the armature coil. A single screw having a rounded head is installed at the position one-fifth of a magnetic pole width apart from the position detector sensor. This type of placement provides for a larger starting torque with a lower starting voltage.
U.S. Pat. No. 5,093,599 relates to a brushless direct current motor comprising a stator base whose two side discs have notches and feet that the polar plates can engage with. The feet pass through the two polar plates and the holes of a circuit board.
U.S. Pat. No. 5,179,307 relates to a variable speed, reversible, brushless direct current motor. The motor comprises a rotor, electromagnets, a switching transistor module, and an electronic controller module. The rotor is mounted on a shaft with bearings at each end, with a plurality of permanent magnets symmetrically placed thereon in an alternating field pattern. Each electromagnet invokes a magnetic field at two permanent magnet positions to cause rotation of the rotor.